Hydrocarbons are organic compounds made primarily of carbon and hydrogen atoms. The addition of chlorine to the carbon-hydrogen chemical backbone increases the stability and decreases the flammability of the resulting compounds. Chlorinated hydrocarbon compounds are a diverse group of compounds, some of which are widely used in industrial and leisure activities. Common chlorinated hydrocarbons include carbon tetrachloride, methylene chloride, and trichloroethylene. These solvents have characteristic slightly pungent odors. They are used extensively in industry as cleaning, degreasing, and thinning agents because of their excellent solvent properties and low flammability relative to other effective solvents. They are also used in the manufacture of other chemicals including plastics and pesticides. Because of their high volatility and low boiling point, workplace exposures may be greater than anticipated. At high temperatures, these substances may decompose to yield highly toxic gases such as phosgene and hydrogen chloride. They are commonly encountered as mixtures with variable toxicity depending on the concentration of individual constituents.
Carbon tetrachloride is used infrequently due to its relative potency as a liver and kidney toxin. Methylene chloride (dichloromethane) is a common constituent of paint strippers, is very volatile, and can accumulate substantial amounts in enclosed spaces; it is metabolized to carbon monoxide and results in elevated carbon monoxide levels extending about 2.5 times longer than with carbon monoxide inhalation. In a small number of people, trichloroethylene will produce "degreaser's flush," a transient reddening of the face and neck, which occurs when the individual consumes even small quantities of alcohol. Sometimes this reaction may also produce a sensation of fullness in the chest and breathlessness.
As a class, the chlorinated hydrocarbons are potent central nervous system depressants or stimulants. They also cause greater liver and kidney damage compared to other organic solvents. Many have been shown to cause cancer in laboratory animals; due to widespread industrial use, the issue of carcinogenic risk to humans is one of the most controversial issues in regulatory toxicology. The chlorinated hydrocarbons have been implicated in causing sudden death at high exposure levels possibly related to the development of heart arrhythmias (ventricular fibrillation).
Exposure to chlorinated hydrocarbon compounds in the occupational setting is primarily through inhalation. Skin absorption is variable and usually insignificant, although dermal absorption following prolonged or extensive skin contact can cause systemic toxicity. |
Source: Medical Disability Advisor
| Individuals exposed to high levels of industrial and environmental pollutants are at higher risk. |
Source: Medical Disability Advisor
History: An individual presenting with acute effects of chlorinated hydrocarbon toxicity may have symptoms of dizziness, headache, nausea, vomiting, sleepiness, fatigue, "drunkenness," slurred speech, vertigo, disorientation, depression, and loss of consciousness. Additional symptoms include sore nose, sore throat, and cough.
Chronic effects of chlorinated hydrocarbon toxicity include dermatitis (red, dry, cracked skin), neurobehavioral dysfunction (headaches, mood changes, memory loss, difficulty concentrating, decreased attention span, and fatigue), liver damage (abdominal pain, nausea, jaundice, abnormal liver function tests) and kidney damage (weakness, fatigue, polyuria, glycosuria, electrolyte abnormalities). Both liver and kidney damage may result from severe acute poisoning. Physical exam: The main signs of chlorinated hydrocarbon toxicity are central nervous system (CNS) effects such as depression or excitation, agitation, lethargy, intoxication, confusion, and unconsciousness. There may also be signs of respiratory distress, visual hallucinations, cardiac dysrhythmias, and seizures. Tests: Measuring the amount of the chemical in the breath is one way of testing for either trichloroethylene or tetrachloroethylene exposure. The breath test, if it is performed soon after exposure, can detect if the individual has been exposed to a small amount of trichloroethylene. Because it is stored in the body's fat and slowly released into the bloodstream, tetrachloroethylene can be detected in the breath for weeks following a heavy exposure. Both trichloroethylene and tetrachloroethylene and trichloroacetic acid (TCA), a breakdown product of both chemicals, can be detected in the blood.
These procedures are useful only if the exposure is recent (within weeks or less), because both solvents are rapidly eliminated from the body. In addition, samples of blood and urine tests can be used to identify the chemicals and their breakdown products in individuals suspected of being exposed to both trichloroethylene and tetrachloroethylene.
A chest x-ray or ECG monitoring may be necessary. |
Source: Medical Disability Advisor
| Treatment is non-specific and includes removal from exposure, decontamination and supportive care (oxygen). Benzodiazepines (psychotropic drugs) are administered for seizures. |
Source: Medical Disability Advisor
| The prognosis for full recovery from exposure to low levels or brief exposures at high level is good where immediate and appropriate treatment is begun. In cases where severe, irreversible damage has been done to the kidney, liver or brain, long-term disability may be anticipated. |
Source: Medical Disability Advisor
| A pre-existing disease of the same affected organ system may complicate this condition. |
Source: Medical Disability Advisor
The Occupational Safety and Health Administration (OSHA) legal airborne permissible exposure limit (PEL) is 100 parts per million (ppm) trichloroethylene averaged over an 8-hour work shift, 200 ppm not to be exceeded during any 15-minute work period, and 300 ppm for 5 minutes in any 2-hour work period. The National Institute of Occupational Safety and Health (NIOSH) recommended airborne exposure limit is 25 ppm trichloroethylene averaged over a 10-hour work shift. The American Conference of Governmental Industrial Hygienists (ACGIH) recommended airborne exposure limit is 50 ppm trichloroethylene averaged over an 8-hour work shift and 100 ppm as a short-term exposure limit (STEL).
The Occupational Safety and Health Administration (OSHA) legal airborne permissible exposure limit (PEL) is 100 ppm tetrachloroethylene averaged over an 8-hour work shift and 200 ppm, which should not be exceeded at any time. The National Institute of Occupational Safety and Health (NIOSH) recommends that occupational exposure to carcinogens be limited to the lowest feasible concentration. The American Conference of Governmental Industrial Hygienists (ACGIH) recommended airborne exposure limit is 25 ppm tetrachloroethylene averaged over an 8-hour work shift and 100 ppm as a STEL.
Exposed workers should work in well-ventilated areas if possible, immediately wash exposed skin areas, and wear protective gear as indicated. |
Source: Medical Disability Advisor
| If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case. Regarding diagnosis:
- Has diagnosis of toxic effects of chlorinated hydrocarbon solvents been confirmed?
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Is there a positive history of chlorinated solvent exposure in the workplace?
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Is the clinical illness, including the history, physical examination, and laboratory findings, consistent with other case descriptions of chlorinated hydrocarbon toxicity?
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Are the whole blood and urine levels of chlorinated solvents and/or their metabolites at or near the normal value?
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Is timing between exposure and clinical onset compatible with the known biologic facts about the hazard?
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Is the exposure dose within the range of doses believed to cause such effects?
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Has individual experienced any complications related to the toxicity?
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Does individual have an underlying condition that may impact recovery?
Regarding treatment:
- What specific treatments did individual receive?
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Would individual benefit from additional or continued therapy?
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Was an x-ray or ECG necessary?
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Were benzodiazepines administered for seizure control?
Regarding prognosis:
- Are there special attributes of the particular individual that make it more or less likely that he or she would be so affected?
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Could chlorinated solvent exposure be occurring outside the workplace (i.e., in the home or community, or in recreational activities)?
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Has individual recently worked in another organization where exposure is higher?
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If occupational duties put individual at risk of exposure, is protective gear provided? Has individual been instructed in its proper use?
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Source: Medical Disability Advisor
| General "Hydrogen Chloride." OSHA. U.S. Department of Labor. 22 May 2005 <http://www.osha.gov/SLTC/healthguidelines/hydrogenchloride/index.html>. |
Source: Medical Disability Advisor
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